The present application relates generally to packaging for containing various products. More particularly, the present application relates to an easy open flow wrapper to be used in any packaging process such as horizontal or vertical form, fill, and seal (FFS) suitable for rigid or semi-rigid products.
Generally speaking, most rigid or semi-rigid articles that are packed in a flow wrapper using horizontal or vertical FFS equipment are done at extremely high packing speeds. The principle of a horizontal flow wrapper machine, for example, is that a flat film is formed into a tube through a folding box and after forming the tube, a set of rotating sealing wheels makes a longitudinal seal, e.g. a fin seal or lap seal. The sealing wheels making the longitudinal seal are responsible for the transport through the machine together with some guiding wheels. The products move over a horizontal conveyer belt and run via the folding box into the formed tube. Once the product is placed into the tube, the cross-seals, also call end seals, are formed through the cross-sealing jaws. In most applications, the end seal of a flow wrapper is formed together with the beginning seal of the following flow wrapper. During sealing, the film is cut to split the adjacent flow wrapper and the cutting knife is generally built into the sealing jaws.
A standard flow wrapper is typically opened at a profiled end seal, which typically contains serrations that aid in the opening of the flow wrapper. This tear is generally not guided, which means that the opening is unpredictable and does not allow for controlled opening of the flow wrapper. A particular problem occurring in the opening of a flow wrapper in the cross direction with pre-cuts or other opening initiations is that these various opening mechanisms are stopped by either the product contained therein or the longitudinal seal of the flow wrapper, which is generally situated in the middle of the flow wrapper. Thus, once the tear reaches the product or this longitudinal seal the tear stops or becomes unpredictable. Furthermore, if the tear power is increased, a piece of the flow wrapper generally brakes off, or the tear continues in a random, unpredictable way.
Various solutions have been offered to address this unpredictable nature in tearing a flow wrapper. One of these solutions suggest pre-cutting/scoring of the flow wrapper at the sides of the tube or on the longitudinal seal. This would allow the consumer to tear across the flow wrapper exposing the product while allowing the consumer to eat out of the wrapper, which provides a clean, mess free experience. However, the issue with this approach is the tear is not typically controllable across the flow wrapper and in the case where the cut is not made in the longitudinal seal the tear is generally stopped by the seal thereby making the tear unpredictable.
Other solutions have been proposed such as the inclusion of a tear strip in the flow wrapper. This tear strip is sealed to the inside of the flow wrapper and allows the tear to be guided along the tape. However, if a tear tape is affixed to the flow wrapper in the cross direction, the tear will still stop at the longitudinal seal while tearing the flow wrapper beginning from the tear tape initiation. Furthermore, most of the tear tapes in the market are not heat-sealable but rather cold-sealable with a pressure sensitive adhesive already on the tape, which disadvantageously results in high costs and negative effects on the packing speeds.
Another proposed solution is perforation of the flow wrapper to achieve easy opening and more opening predictability. This perforation can be achieved either by die cutting or laser scoring the flow wrapper. Although such perforation can achieve an easy opening and more predictable opening feature, the depth of the perforation must be precisely controlled or a piece of the flow wrapper can break off during packing due to the web being under tension during the filling process. Furthermore, the depth of the perforation must be controlled to prevent barrier loss, thus the perforation must be performed within a sealed area.
Thus, there exists a need to provide an easy open flow wrapper that can be opened with predictability and minimal force without prematurely opening or separating during manufacturing or packaging, with minimal loss, if any, of its barrier properties, and capable of being utilized on standard packaging equipment without significant reduction in packaging speed.